To evaluate the feasibility and accuracy of a three-dimensional augmented reality system incorporating integral videography for imaging oral and maxillofacial regions, based on preoperative computed tomography data. Three-dimensional surface models of the jawbones, based on the computed tomography data, were used to create the integral videography images of a subject's maxillofacial area. The three-dimensional augmented reality system (integral videography display, computed tomography, a position tracker and a computer) was used to generate a three-dimensional overlay that was projected on the surgical site via a half-silvered mirror. Thereafter, a feasibility study was performed on a volunteer. The accuracy of this system was verified on a solid model while simulating bone resection. Positional registration was attained by identifying and tracking the patient/surgical instrument's position. Thus, integral videography images of jawbones, teeth and the surgical tool were superimposed in the correct position. Stereoscopic images viewed from various angles were accurately displayed. Change in the viewing angle did not negatively affect the surgeon's ability to simultaneously observe the three-dimensional images and the patient, without special glasses. The difference in three-dimensional position of each measuring point on the solid model and augmented reality navigation was almost negligible (<1 mm); this indicates that the system was highly accurate. This augmented reality system was highly accurate and effective for surgical navigation and for overlaying a three-dimensional computed tomography image on a patient's surgical area, enabling the surgeon to understand the positional relationship between the preoperative image and the actual surgical site, with the naked eye.
Calibration ; Data Display ; Feasibility Studies ; Humans ; Image Processing, Computer-Assisted ; instrumentation ; methods ; Imaging, Three-Dimensional ; methods ; Mandible ; anatomy & histology ; Maxilla ; anatomy & histology ; Models, Anatomic ; Optical Devices ; Oral Surgical Procedures ; instrumentation ; methods ; Pilot Projects ; Stereotaxic Techniques ; instrumentation ; Surgery, Computer-Assisted ; instrumentation ; methods ; Tomography, X-Ray Computed ; methods ; Tooth ; anatomy & histology ; User-Computer Interface ; Video Recording ; instrumentation ; methods

The purpose of this study was to evaluate the usefulness of thallium-201-chloride (Tl-201) scintigraphy for the examination of patients with tumors of the head and neck, and to estimate the correlation of the expression of Na⁺/K⁺-ATPase with Tl-201 scintigraphy. Tl-201 scintigraphy was performed in 61 patients with squamous cell carcinoma and 10 patients with benign tumors of the salivary gland. The tumor retention index was obtained from the early and delayed dynamic Tl-201 scintigraphies. The expression of Na⁺/K⁺-ATPase on the cell membrane was evaluated immunohistochemically. Evaluation of correlations between the histopathological tissue differentiation of tumors, the tumor retention index of Tl-201 scintigraphy and the expression of Na⁺/K⁺-ATPase was performed. The tumor retention index of Tl-201 scintigraphy correlated well with the histopathological tissue differentiation of tumors and also showed a good correlation with the expression of Na⁺/K⁺-ATPase. In addition, the expression of Na⁺/K⁺-ATPase demonstrated a close correlation with the histopathological tissue differentiation of malignant tumors. The tumor retention index could be used for the differentiation of malignant tumors from benign tumors and the expression of Na⁺/K⁺-ATPase was estimated as one of the most important factors for Tl-201 accumulation in malignant tumors.